Touchpad is designed to be an input device. For performing all of its functions such as controlling the movement corresponding to a point, it can be touched or slipped by a finger or a conductive object. Owing to its easy operation, therefore, it is widely applied to electronic products, including portable computer, personal digital assistant (PDA), mobile phone, and etc.
Additionally, for supporting more functions on the limited space, of the touchpad space is improved to comprise more than two operation areas.
FIG. 1 is a diagram of a conventional touchpad 10 having four operation areas placed in the corners respectively. The four operation areas, CR1, CR2, CR3, and CR4, are referred to as “corner function areas”, and generally, they are acted as suppositional function keys having their own corresponding functions. Hence, a related function can be performed when one of the corner function areas is touched by finger 12.
FIG. 2 is a diagram of a touchpad 20 having two scroll function areas. The scroll function areas, SCROLL1 and SCROLL2, have their own corresponding function of rolling scrolls on Window. Similar to the touchpad 10 of FIG. 1, a further function can be performed when the scroll function area SCROLL1 or SCROLL2 is slipped by the finger 12.
For more convenient operation, more function areas are individually programmed within the touchpad limited space. In further consideration, hence, some function areas must be reasonably overlapped together to save the usable space. However, an indefinite command mistake will be easily resulted without any detection methods of distinguishing the accurate commands from a user when the overlapped function area is touched.
FIG. 3 is a diagram of a touchpad 30 having corner function areas and scroll function areas. As shown in FIG. 3, the scroll area SCROLL1 overlaps the corner function areas CR1 and CR2, and the scroll area SCROLL2 overlaps the corner function areas CR2 and CR3. Conventionally, the corresponding functions are performed when the corresponding corner function areas thereto are touched. However, the touchpad is installed inside a case slot, and there exists a gap surrounding the touchpad, as shown in FIG. 4. Thus, when a user touches a corner function area and a finger is placed on the gap between the case and the touchpad, obviously, a function corresponding to the corner function area may be missed because of incomplete or soft touching input.
Otherwise, when the finger 12 touches the corner function area CR1 of the touchpad 30, for example, the touching angle of the finger 12 will be mistaken to be a movement pressed on the scroll area SCROLL1.